Electric switch



` Oct. l, 1929. C, D AINSWORTH 1,729,860

ELCTRIC swITcH Filed Feb. 18, 1927 Patented Oct. 1, 1929 UNITED STATES PATENT OFFICE CHESTER D. AINSWORTH, OF WOLLASTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELECTRICAL MANUFACTURING CORPORATION, 0F SOUTH BOSTON, MASSACHUSETTS,

A CORPORATION 0F MASSACHUSETTS ELECTRIC SWITCH vApplication filed February 18, 1927.

This invention relates to electric switches of the oil type having stationary terminals and a movable bridge member.

An object of this invention is the provision of a bridge member having a large surface area compared with its cross sectional area to obtain relatively high heat radiation whereby the bridge member can carry relatively high values of current without excessive heating.

Another object of the invention is the improved construction of the auxiliary stationary and movable'arcing members.

These and other objects, which might hereinafter' appear, are attained in the embodiment of the invention herein shown and described.

F ig. 1 shows an oil switch embodying the present invention.

Fig. 2 is a side view of the stationary and movable switch members.

Fig. 3 is an end view of the switch members shown in Fig. 2.

Fig. 4 is a plan view of a stamped blank from which the bridge member is formed.

Fig. 5 is a side view of the bridge member formed from the blank shown in Fig. 4.

Fig. 6 is a perspective view of the bridge member formed from the blank shown in Fi, 4.

is here shown, a switch casing 10 is provided with oil immersed stationary Contact terminals 11 and 12 having main currentcarrying members comprising inverted brush-members 13 and 14, a bridge member 15 secured to the operating rod 16, and cooperating auxiliary Contact, or arcing members 17, 18 and 19, 20.

The bridge member 15 is formed from a stamped blank of copper 15 of substantially the shape shown in Fig. 4 by bending the blank along the dotted lines a and otherwise shaping the blank to provide the channelconstruction shown in Fig. 6 which comprises a broad and flat contact section 15al having an aperture 15b in the middle thereof and depending sections or sides 15c and 15d having inwardly directed end extensions 15e and 15f. These end extensions, at the tops thereof, have horizontally disposed inwardly di- Serial No. 169,362.

rected apertured ears 15g and 15h to which the arcing members 18 and 20 are adapted to be secured.

The sides 15c and 15d and the intermediate Hat Contact section l5a have a relatively great heat-dissipating surface for a relatively' small cross-sectional area, as compared with the usual bridge member, whereby to provide a high current-carrying capacity for a relatively small mass of copper. The sides 15c and 15d impart rigidity to the bridge member and increase the current carrying capacity and heat radiating surface of the bridge member making unnecessary a comparatively massive contact section.

The bridge member l5 is mounted on the reduced portion 16 of the insulating operating rod 16 and can rock slightly thereon in a vertical direction for the purpose of seating upon the brush members but is held from rotation on said rod. For this purpose, a plate 21 is positioned between the sides 15c and 15d and is rigidly secured to the shouldered end 16a of the operating rod 16.

The construction of the arcing members 17, 18 and 19, 20 is best shown in Fig. 3. The arcing member 17 is a substantially U-shaped resilient integral strip secured to the contact terminal by screws 17 and preferably provided with arcing tips 17a and 17". The arcing member 19 is of the same construction. The movable arcing member 18, cooperating with the arcing member 17, is of general inverted W-shape and comprises an integral strip of metal having an intermediate sec'- tion 18a which is secured to the apertured ear 15g of the bridge member 15, and depending outwardly directed Contact sections 18b and 18C formed with bends 18d and 18e which impart. a slight resiliency thereto. The'movable auxiliary arcing member 20 that cooperates with the arcing member 19 is of the same construction as the arcing member 18. The members 17, 18 and 19, 20, thus constructed cooperate in a comparatively long wiping action therebetween.

The construction and arrangement of parts may be modified without departing from the spirit of the invention.

I claim:

l. In an electric switch, the combination of stationary switch members comprising spaced brush members, and a movable bridging member comprising a stamping consisting of a flat plate of uniform thickness having opposed and downwardly Vreflexed sides forming with the body of the plate, .achannel member, the body ofvsaid plate between said reflexed sides presenting a continuously fiat upper face providing a contact face for said brush members.

2. In an electric switch, a movable bridging member characterized by being formed from a single piece of sheet metal reflexed to provide integral Aopposed depending .side

walls and an' integral top connecting wall 'which-has a continuously flat contacting upper face from end to end.A

3. In' an oil switch, a bridge member consisting of an inverted channel having a fiat 'ii J )er contact section s `aced de IidinfY integralv walls, and arcing members located at and spaced away from the ends of said channel, the space within and below and at the sides -of the channel being clear and unob` strueted to permit free flow of a cooling medium. i

4. In an oil switch, a bridge member having a middle contact section'and depending sides having integral arcing-member sup- 'p'ortingextensions which are extended transversely of the middle section.

5. In an oil switch, a. bridge member comprising an integral stamping consisting of a flat plate of uniform thickness 'reflexed to provide, as integral parts, a middle contact section, depending sides, and extensions integral with said sides adapted to carry auxiliary contactmembers. 6. A bridging member lfor an electric switch comprising a flat plate having integral depending side-members provided with oppo- Ysitely-directed end-extensions having oppositely-directed laterally-reiexed ears providing seats for contact-members.

7. In an oil switch, stationary terminals, a movable bridge member cooperating therewith and comprising a middle Contact section and depending sides, an operating rod on which said bridge member is mounted, and means to prevent rotary movement of said Vbridge member 0n said rod including means fixed to said rod and disposed between and having opposed faces parallel with and loosely engageable with said depending sides on opposite sides of said rod.

8. In an oil switch, an auxiliary arciiig member comprising an integral U-sliaped resilient strip arranged to be'secured to a support at the middle of the strip and having free depending contact arms.

9. In an oil switch, an auxiliary arcing member comprising an integral U-shaped resilient strip and arcing tips fixed to the ends of said strip.

l0. In an oil switch, an auxiliary arcingr member comprising a single member having integral depending side contact sections hav- ,ing bends therein intermediate the contact sections for imparting resiliency thereto.

1l. In an oil switch, cooperating stationary and movable Contact members, one of said members comprising an integral `U.,Sl 1aped resilient strip having arcing tips at the ends thereof, and the other contact member comprising a strip of general inverted W-shape having opposed contact sections adapted to be yieldingly engaged lby said arcing tips.

l2. In an oil switch, cooperating station` ary and movable Contact members, one of said members comprising an- 'integral U- shaped resilient strip including a bottom connecting portion and depending end portions having arcing tips at theends thereof, said member being supported intermediate its bottom connecting portion, and the other contact member having integral opposed depending Contact sections hav-ing bends therein for imparting resiliency thereto, said contacts having a yielding wiping action on each other.

In testimony whereof, I have signed my name to this specification.

CHESTER D. AINSVVORTH.

lll!) 

